The present invention relates to an arrangement incorporating a carburetor discharging a rich fuel mixture to a heat exchange vaporizer prior to mixing with main combustion air for fueling an engine. More particularly, the vaporizer utilizes waste heat from the exhaust of the engine.
It is known that gasoline-type internal combustion engines consume a significant amount of gas and produce noxious emissions. Such engines typically utilize a conventional carburetor or fuel injection systems. Such systems require a liquid fuel which is atomized and mixed with air to render it suitable for combustion. Carbureted or injected systems further dictate the proportions of gasoline and air required for varying engine operation. Such systems provide the desired amount of gasoline and air for conditions including normal driving, acceleration, hill climbing and sustaining speeds.
Successful and complete vaporization of the liquid fuel has been a goal sought by many. Incomplete vaporization result in raw liquid being ingested into the engine""s combustion chamber resulting in poor efficiency and pollution. This situation is further exacerbated in low operations such as under low engine speed where air flow is low and energy to vaporize fuel is lowest. Fuel injection has gone a long way to maximize atomization, however there has been little relief for the large number of carbureted vehicles still in service.
In the group of carbureted fuel delivery systems, there have been attempts to maximize vaporization through means other than mere atomization and mixing with the stream of combustion air. Such technology includes that disclosed in U.S. Pat. No. 4,469,077 to Wooldridge illustrates a carburetor in which the entire fuel and air mixture is sent through an exhaust gas heat exchanger prior to reaching the engine rich mixture intake. The carburetor is conventional with only the resulting mixture being piped from the carburetor, to the heat exchanger adjacent the exhaust and back to the intake engine.
Further, in U.S. Pat. No. 5,140,966 to Wong, fuel enters a reservoir upon which an ultrasonic plate vaporizes the fuel and a fan blows a small amount of air and the fuel vapor through a heat exchanger heated by exhaust gas. The resulting heated fuel and air is finally commingled with a main air steam before reaching the engine""s intake. Both ultrasonic agitation and heat are used to improve fuel vaporization and are located remote from the engine intake.
Prior art systems are characterized by independent, large and expensive systems for adapting existing carburetors or replacing carburetors.
There is a demonstrated need for a carburetor which is capable of substantially complete vaporization of the liquid fuel and resulting in even distribution between engine cylinders so as to completely burn the fuel mixture, reduce emissions and reduce liquid fuel consumption.
An improved carburetor arrangement is provided which improves gas mileage and decreases exhaust emissions. The arrangement is suitable for fitting to substantially any gasoline-burning engine. The arrangement vaporizes substantially all elements in the fuel, and then forming a nearly perfect mix of vapor and air resulting in a balanced distribution to each combustion chamber of the engine. In a preferred arrangement, the vaporizer, the mixing chamber and heat control are all assembled into one unit, fit directly to the intake manifold. As a result, gas mileage is improved, oil stays cleaner longer, engine runs cooler, and fuel emissions are almost nil. As a result of the cooler running engine and cleaner oil the wear and tear on the engine is less and the life of the engine should be longer.
The carburetor arrangement comprises a heat exchanger or vaporizer which conditions the fuel to produce the maximum allowable power and a minimum amount of emissions. One disadvantage in the prior art, as pointed out by Wooldridge, is that conventional carburetors are inefficient at lower fuel demands; lower fuel demand being exactly the objective when reducing gas consumption in a stock power train. The present arrangement uses a low-capacity fuel/air regulator or carburetor for efficiently vaporizing rich mixtures of fuel and subsequently later mixing the rich mixture with more air to obtain stoichiometric amounts for combustion. The rich mixture is fed into the vaporizer to allow this small amount of air and fuel to be heated and completely vaporized. Simply, the low-capacity carburetor allows this efficiently mixed, rich vapor to be heated for subsequent mixing with a larger amount of incoming fresh combustion air, at a regulated amount, and which is then which distributed. The main air and rich mixture preferably pass through a mixing chamber before the engine intake. Further, the carburetor arrangement is conveniently and simply contained in one sealed annular unit which connects to the engine intake at the conventional intake manifold.
In a broad aspect of the invention, a carburetor arrangement is provided for admitting fuel and stoichiometric amounts of air to an engine having an engine fuel mixture intake having a throttle regulator and discharging hot exhaust gas, the carburetor arrangement comprising: a main combustion air gallery connected to the engine intake having a main air regulator for admitting a substantially stoichiometric amount of air; a vaporizer having an exhaust gas passage therethrough connected to the engine""s exhaust gas, and a fuel passage therethrough and having a fuel intake and a rich mixture discharge into the main combustion air gallery, the exhaust and fuel passages being isolated by a heat exchange barrier; and a fuel/air regulator connected to the fuel intake, the fuel/air regulator metering fuel and a carrier air into the fuel passage, the amounts of carrier air being less than a stoichiometric amount and only enough to carry the fuel through the fuel passage to the main air gallery.
Preferably the fuel/air regulator is a low-capacity carburetor, such as that used for motorcycles and snowmobiles.